Pulsed laser sources, such as Nd:YAG lasers, have been used to perform laser-based material processing for applications such as marking, engraving, micro-machining, and cutting. Many existing high power pulsed lasers that are characterized by pulse energies greater than 0.5 mJ per pulse, rely on techniques such as Q-switching and mode locking to generate optical pulses. However, such lasers produce optical pulses with characteristics that are predetermined by the cavity geometry, the mirror reflectivities, and the like. As such, the characteristics of such laser pulses cannot generally be varied in the field without compromising the laser performance. Using such lasers, it is generally difficult to achieve a range of variable pulse characteristics.
Pulsed laser sources such as diode lasers can be pulsed in a simple manner by providing a pulsed electronic drive signal. However, the center wavelength of the signal from such a pulsed laser source may change and the signal linewidth may also be broadened as the electronic drive signal is applied, which may be strongly dependent upon the current level of the drive signal. One undesirable result of such broadened linewidth is to significantly reduce the efficiency of the harmonics generation using frequency doubling, tripling, and the like. Thus, there is a need in the art for developing stable pulsed laser sources with tunable pulse characteristics.